I would like to pay attention to the article "Words and More Words" by Joseph Malkevitch. Here are a few intriguing references:
M. Morse, A solution of the problem of infinite play in chess, Bull. Am. Math. Soc., 44 (1938) 632.
M. Morse and G. Hedlund, Symbolic dynamics, Am. J. Math. 60, (1938) 815–866.
Lothaire, M. Applied Combinatorics on Words, Cambridge U. Press, New York, 2005.